Walter c



(No Model.)

v w. 0. WESTAWAY. MACHINE FOR ROLLING SHEET METAL INTO UURVED FORMS.

Patented Mar. 22,1892.

UNITED TATES -ATENT Fries.

WALTER O. IVESTAWVAY, OF DECORAH, IOWA, ASSIGNOR TO THE DECORAHVVINDMILL COMPANY, OF SAME PLACE.

MACHINE FQR RQLLING SHE ET METAL INTO CURVED FORMS.

SPECIFICATION forming part of Letters Patent No. 4'71,407, dated March22, 1892.

Application filed February 26, 1891. Serial No. 382,958. (No model.)

To all whom it may concern:

Be it known that I, WALTER O. WESTAWAY, a citizen of the United Statesof America, residing at Decorah, in the county of I/Vinne shiek andState of Iowa, have invented a certain new and useful Improvement in theart of Rolling Sheet Metal into Curved Forms,

of which the following is a specification.

in its mode of application to vary the specific form of result.

Figure 1 is a side elevation of the machine; Fig. 2, a vertical sectionin line 2 2 of Fig. 1; Fig. 3, an edge view of the form of sheet metalproduced by the rolls shown in Figs. 1 and 2; Fig. 4, an end view of thesheet shown in Fig. 3; Fig. 5, a modification of the rolls; Figs. 6 and7, side and end views, respectively, of the form of. sheet produced bythe rolls shown in Fig. 5; Fig. 8, another modification of the rolls;and Figs. 9 and 10, side and end views, respectively, of the form ofsheet produced by the rolls of Fig. 8.

My invention is based on the discovery made by me that if a sheet of anymetal capable of upsetting or becoming permanently altered in form bypressure be passed between two rolls, one of which is convex and theother concave, not only will the resulting form of the sheet be curved,but the specific form of its curvature will depend upon the way in whichthe rolls bite the sheet as it passes between them, and hence that byvarying the bite of the rolls metal sheets may be caused to assume agreat variety of useful or ornamental curved forms by the simple processof rolling. This fact and its underlying mechanical principle can bestbe explained by reference to the illustrative drawings.

The machine shown in Figs. 1 and 2, except as to the form of its rol-ls,is an ordinary' rolling-machine, known to every mechanic, and thereforerequiring no specific description, except so far as may be necessary tovpoint out the factthat one of the two rolls isconvex and the otherconcave and that .one of them is preferably mounted in sliding bearingsheld to their seat by the action of stout springs S, adapted foradjustment of the pressure by means of adjusting-screws s s. I havediscovered that if a pair of rolls A B of this general form be so shapedand set as' to bite or press upon the metal somewhat harder at and neartheirpnds than at other points and the sheet be fed between them theresulting form of sheet will be substantially such as is outlined inFigs. 3 and 4- that is to say, its cross-section or end view willexhibit the reversed curves of Fig, Land its side view the slightlongitudinal curve of Fig. 3. The increased pressure at and near theends of the rolls is indicated in Fig. 1 by the convergence of theiroutlines at the points marked city. If, on the other hand, the rolls beformed and set, as shown in. Fig. 5, so that the increased bite comes atand. near the middle, as indicated at an, the resulting form of sheetwill be substantially as represented in Figs. 6 and 7, having thesemicircular orapproximately semicircular crosssection of Fig. 7 and thecircular longitudinal bend of Fig. 6. Again, if the rolls be formed vand set, as shown in Fig 8,so that the increased bite comes at each sideof the middle line and a short distance therefrom, as indicated at a a,the resulting form of 'sheet will be longitudinally straight, asrepresented in Fig. 9, but semicircular or approximatelysemicircularincross-section, as shown in Fig. 10. These illustrationswill suffice to'show that by varying the position of the biteAor zone ofgreatest pressure in a pair of rolls, one of which is convex and theother concave, the manufacturer can produce a corresponding variety ofuseful products by the simple process of rolling between two rolls notheretofore known to be available for such purpose.

It would be impracticable to attempt to illusthe difierent results,which depend in part upon the degree of curvature of the rolls and inpart upon the drawing effect of the unequal bite and of the differentialspeed of the rolls along their line of contact with the sheet metal.

The drawings exaggerate the increase of bite in order to render the factvisible to the eye. In practice the space between the rolls needs to bevaried only minutely, and the variation would hardly be perceptible inthe full-sized roll, much less in the reduced drawlng.

As an example of the utility of this invention I would state that I havefor some time been rolling sheet-metal sails for windmills in a machinehaving the form of rollsrepresented in Fig. 8. The sheet-metal blanks inthis case are about one-sixteenth inch thick, three feet long, nineinches wide at the wider end, anduthree inches wide at the narrower end,and are fed endwise to the rolls. They come out of the machine curved incross-section, but straight longitudinally, and ready for immediateapplication to the windmill. Other manufacturers make the same form ofsail by the use of a drop-press or by feeding sidewise through a threc-roll rolling-machine; but, as compared with the work of suchmachine, the increased output and the saving of labor etfected by myimproved process of rolling enable me to save about four-fifthsof thecostof manufacture, besides producing sails which retain their curvaturemore permanently than those made with the three-roll machine or with thedrop-press.

I am aware that in forming articles of sheet metal by means of rolls itis common to so shape the rolls as to leave a space between them towhich the sheet conforms itself as it passes throughfor example, bybeading one rolls and is not due to pressure alone noreffected by anaction similar to that of dies nor by an action like that of spinningrolls or disks. On the contrary, it is due to the un equal draft or tgnsile strain upon the metal, causing the sheet to 01 transversely andto issue from the rolls in a form which is determined by the position atwhich the lines of greater strain have been applied to it, and not atall corresponding to the form of the space through which it has passed.Thus in Figs. 4, 7, and 10 the transverse section of the resulting sheetdoes not correspond to the shape of the space seenbetween the rolls inFigs. 1, 5, and 8, and therefore cannot have been produced by thepressure alone.

I am aware thatin the patent to S. E. Nichols, dated February 5,1867,No. 61,856, it was proposed to bend narrow strips of sheet metallongitudinally by pinching one edge between rolls. Such longitudinalbending, while produced by some modifications of my rolls, as in Figs. 1and 5, is not by others, (see Fig. 8,) and is therefore merelyincidentaland wholly immaterial to my invention.

At the middle of my rolls the convex surface travels faster than theconcave, and therefore produces adrawing strain upon one side of thesheet along its middle line. At the ends oi the rolls the concavesurfaces travel faster than the convex, and therefore produce drawingstrains upon the other side of the sheet along its lateral lines. Atsome intermediate point between the middle and each end the opposed rollsurfacestravel at equal speed, and no strain is produced. I havediscovered that if under such conditions the rolls be caused to pinchthe sheet metal at or near their middle or at- QI' near their ends morestrongly than at otherpoints the resultant of the tensile strains willbe such as to cause the sheet to curl up transversely as it issues frombetween the rolls, taking a shape which is determined by the positionofthe point or points at which the greater pinching is applied, and byutilizing this discovery in the manner herei'nset forth I have beenenabled to effect a great practical and economical improvement in themanufactureot' various kinds of sheet-metal ar' ticles. 1

Having thus described my invention, What I claim as new, and desire tosecure by Letters Patent, is-- In a sheet-metal rolling or formingmachine, the combination of convex and'concavc rolls A B, constructedand arranged to present along their lines of pressure on the metal sheetzones or regions a, constructed to bite with unequal force in diiferentplaces along the'line of contact with said sheet, substantially asdescribed.

\VAIQER O. VESTAXVAY.

IVitnesses:

W. M. HILL, L. IIILL.

